<template>
  <div>
    <input ref="excel-upload-input" class="excel-upload-input" type="file" accept=".xlsx, .xls" @change="handleClick">
    <div class="drop" @drop="handleDrop" @dragover="handleDragover" @dragenter="handleDragover">
      <!-- 上传设备表 -->
      <el-button :loading="loading" style="margin-left:16px;" size="mini" type="primary" @click="handleUpload">
        上传设备表
      </el-button>
    </div>
  </div>
</template>

<script>
import XLSX from 'xlsx'
import { uploadExcel, loadExcelData } from '@/api/uploadExcel'
export default {
  props: {
    beforeUpload: Function, // eslint-disable-line
    onSuccess: Function// eslint-disable-line
  },
  data() {
    return {
      loading: false,
      excelData: {
        header: null,
        results: null
      }
    }
  },
  async mounted() {
    this.listLoading = true
    try {
      const results = await loadExcelData()
      this.generateData({ results })
    } catch (error) {

      this.listLoading = false
    }
    setTimeout(() => {
      this.listLoading = false
    }, 1 * 1000)
  },
  methods: {
    generateData({ results }) {
      this.excelData.results = results.data
      this.onSuccess && this.onSuccess(this.excelData)
    },
    handleDrop(e) {
      e.stopPropagation()
      e.preventDefault()
      if (this.loading) return
      const files = e.dataTransfer.files
      if (files.length !== 1) {
        this.$message.error('Only support uploading one file!')
        return
      }
      const rawFile = files[0] // only use files[0]

      if (!this.isExcel(rawFile)) {
        this.$message.error('Only supports upload .xlsx, .xls, .csv suffix files')
        return false
      }
      this.upload(rawFile)
      e.stopPropagation()
      e.preventDefault()
    },
    handleDragover(e) {
      e.stopPropagation()
      e.preventDefault()
      e.dataTransfer.dropEffect = 'copy'
    },
    handleUpload() {
      this.$refs['excel-upload-input'].click()
    },
    handleClick(e) {
      const files = e.target.files
      const rawFile = files[0] // only use files[0]
      if (!rawFile) return
      this.upload(rawFile)
    },
    async upload(rawFile) {
      this.$refs['excel-upload-input'].value = null // fix can't select the same excel

      console.log(rawFile)
      this.listLoading = true;
      const formData = new FormData();
      formData.append('file', rawFile);
      const aaa = await uploadExcel(formData)
      console.log(aaa)
      try {

        const results = await loadExcelData()
        console.log(results.data)
        this.generateData({ results })
      } catch (error) {
        this.listLoading = false
      }

      setTimeout(() => {
        this.listLoading = false
      }, 1 * 1000)
      this.$message({
        title: "",
        message: "上传设备表" + '成功',
        type: 'success',
        duration: 2000
      })
      // if (!this.beforeUpload) {
      // this.readerData(rawFile)
      //   return
      // }
      // console.log(rawFile)
      // const before = this.beforeUpload(rawFile)
      // console.log(before)
      // if (before) {
      //   this.readerData(rawFile)
      // }
    },
    readerData(rawFile) {
      this.loading = true
      return new Promise((resolve, reject) => {
        const reader = new FileReader()
        reader.onload = e => {
          const data = e.target.result
          const workbook = XLSX.read(data, { type: 'array' })
          const firstSheetName = workbook.SheetNames[0]
          const worksheet = workbook.Sheets[firstSheetName]
          const header = this.getHeaderRow(worksheet)
          const results = XLSX.utils.sheet_to_json(worksheet)

          console.log(results)

          this.generateData({ header, results })
          this.loading = false
          resolve()
        }
        reader.readAsArrayBuffer(rawFile)
      })
    },
    getHeaderRow(sheet) {
      const headers = []
      const range = XLSX.utils.decode_range(sheet['!ref'])
      let C
      const R = range.s.r
      /* start in the first row */
      for (C = range.s.c; C <= range.e.c; ++C) { /* walk every column in the range */
        const cell = sheet[XLSX.utils.encode_cell({ c: C, r: R })]
        /* find the cell in the first row */
        let hdr = 'UNKNOWN ' + C // <-- replace with your desired default
        if (cell && cell.t) hdr = XLSX.utils.format_cell(cell)
        headers.push(hdr)
      }
      return headers
    },
    isExcel(file) {
      return /\.(xlsx|xls|csv)$/.test(file.name)
    }
  }
}
</script>

<style scoped>
.excel-upload-input {
  display: none;
  z-index: -9999;
}

.drop {
  /* border: 2px dashed #bbb; */
  width: 600px;
  /* height: 160px;
  line-height: 160px; */
  margin: 0 auto;
  font-size: 24px;
  border-radius: 5px;
  text-align: center;
  color: #bbb;
  position: relative;
}
</style>
